Deserts are vast dry regions with very little rainfall of about 10 inches annually. They cover about 1/5 of the earth's surface. Deserts are a crucial part of the ecosystem despite their extreme climate and they provide habitat for a variety of small animals and plants such as cacti. Although many of the planet's deserts are hot and dry, the two largest deserts, the Arctic and Antarctic, are polar deserts while the Sahara desert is the world's largest hot desert. The following are the four types of deserts.
Hot and Dry Deserts
Dry and hot deserts are the stereotypical deserts familiar to many people. These types of deserts experience very little rainfall, hot temperatures during the day and freezing temperatures during the night. They are characterized by sand, rocks, gravel, and a few sparse oases. The Sahara Desert is the largest hot desert in the world. Others include the Sonoran, Mojave, and Chihuahuan deserts. Large animals are not common in the desert because of the harsh climate. Smaller animals that live in these deserts are nocturnal. The Atacama Desert in Chile is the driest place in the planet with an annual rainfall of less than half an inch. Some deserts can get extremely hot that precipitation evaporates before reaching the ground.
Cold Winter Deserts
Cold winter deserts are also known as semi-arid deserts. They are characterized by dry summers and winters with brief intervals of rainfall. The pattern resembles a hot desert but slightly cooler. Semi-arid deserts are found in North America, Russia, northern Asia, Europe, and Greenland. The average temperature ranges between 21-27°C (70-80°F) while the annual rainfall is between 0.8 and 1.5 inches. The dominant vegetation is cacti because of their ability to reserve water. Many of the animal species spend time in burrows to protect themselves from the extreme temperature. Most of the rodents, reptiles, insects, and birds are active at dusk and dawn when the conditions are tolerable.
Coastal deserts are found in cool to warm regions. They experience cool winters but long warm summers. During the winter, the temperature averages 6°C but can drop to -4 or -5°C. During the summer, the temperature ranges between 13 and 24° Celsius. The annual average rainfall is between 3 and 6 inches. Coastal deserts lie close to the Tropic of Capricorn and Cancer. They include the skeleton coast of Namibia, Angola, and the Western Sahara desert.
Polar deserts are cold deserts. They are located at the earth's poles. They receive annual precipitation of between 6 and 10 inches. The Antarctic is the world largest desert with an area spanning about 5.5 million square miles. The Arctic is the second largest desert with an area of 5.4 million square miles extending across Alaska, Canada, Iceland, Greenland, Sweden, Norway, Russia, and Finland.